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I NITED SATES- Armin-Ann sonAFABnImor MANNHEIM, GERMANY.-

MANUFACTURE OF PURPLEDYEeSTU-FFL ,srnorrrflr'ron forming part or Letters rat-tens na-eeoeeemateaDecember '25,T1ss a.

'Applicaiion filed Septeniberfihddfii. o"specimens") v in chemical literature by the name of tetrainethyldianiido benzophenone,".(Beilsteins Handbook of Organic Chemistry, edit.- 1883, p. 1675,) treating the said derivative with reduc ingor hydrogenizing agents combining the hydrogenized product thus obtained with dimethyl-aniline, submitting the result of such combinatien to an oxidizing process and crystallizing the dye-stud" or coloring-matter thus produced from its solution in suitable solvents.

"In carrying out my invention Itake one hundred parts, by weight, of the above-mentioned tetra-methyl-diamido benzophenone and dissolve the same in abopt one thousand parts, by weight, of amylio alcohol, containing abo'ut sixty parts, by weight, of dry caustic soda in solution. ,I then heat the alkaline solution thus obtained with about eighty parts, by weight, of zinc-dust, at a temperature from 120. to 130" centigrade during about for- ,ty-eight hours, or until the reactionno lonfg'er appears to proceed. This-point may be "ascertained by withdrawing; a.,sample of the said-alkaline solution'from time-to time, and strongly acidifying the same by the addition of glacial acetic acid, whereby a'n'intensclyblue color will be developed. "I consider the hydrogenizing action-to be finished if tlre said blue color of the sample no longer increases tle, and Idraw off the. clear solution into .a still in order to distill oflthe amylic alcohol,

' which may thus be recovered. The residue and afterward dissolved in'an excess of cold 'in intensity. l-then allow zthe mixture to setand dilute hydrochloric acid-' say in a mixture of about one hundred parts, by weight,

of strong hydrochloric acid of "1.18 specific gravity with two hundred and fifty parts of water. The acid solution t-hus obtained is then filtered, and the filtered'liquor is mixed withaboutfifteen hundred parts of water and fractionally precipitated. by the addition ofcausticesoda iiquor,"in' order to separate the hydrogenized product from. any tetrainethyldiamido-benzophenone which may have'remaimed unacted upon by the hydrogenizing 7 mixture of zinc-dust and alkali 'as before de scribed. For thispurpose I add caustic-soda 6'5 liquor until the solution has assumed'a pure blue color, whereby a precipitate is formed .containingtheunalteredtetramethyhdiamidoe; benzophenone, if suchtbe present. I. then. filter and precipitate the filtered solution'by adding. thereto caustic-soda liquor in slight excess. The hydrogenized product thus pre cipitated, and which in chemical language may be called "tetraniethyl-diamido-benzhydrole, is filtered free from alkali by washings with water, pressed and dissolved in about one hundred and fifty parts, by weight, of diluted sulphuricacid, containing about thirty parts, by weight, of rectified sulphuric acid of 66 Bauin. I then add thirty parts, by weight,'of dimethyl-aniline, and the" reaction is allowed to proceed, first, at an ordinary temperature during about twelve hours, and afterward at about 100 centigrade during about three hours, or until the combination (or the so-called condensation) of the hydrogenized product with dimet-hyl-aniliue has been accomplished, which point may be ascertained by the entirechange of the existing blue color of the last-named mixture into apale greenish hue. This point being arrived at, I add caustic-sodaliquor in sufficient excess to liberate the organic bases contained in the said mixture. 1 I then distill off the dimethylaniline whichhas remained unacted upon, and I filter and wash the solid product thus obtained. The said product, which in cliemical language may be called the leuco base, of my new coloring-matter, is then submitted to an oxidizing process analogous to that which is now generally used for converting the leuco bases of malachite-green, or of siini- .l.30 .tiye of ,para-rosanihn'e. v

' also a well crystallized sulphate and oxalate.

lar dyestuffs into their corresponding colon" j ing-matters In the .present instance I dissolve about twenty'parts, by weight, of the said leuco base of my new coloring-matter in 5 about twenty-five parts, by weight, of hydro chloric acid of 1.18 specific grayityand about ninehundred parts of water, and to the solu tion thus obtained I-then add, in the cold and I under constant agitation, about thirteen parts, 7 :trby weight, of peroxide of lead in a state of ro tine-division. The oxidation of the leuco base 'Ybeing accomplished, which is indicated bythe'purple color of the solution no longer increasing in intensity, I then add about twenty .15 parts, by weight, of crystallized sulphate of .s'oda in order to free the solution from lead 'salts, and I precipitate the coloring-matter by theaddition-ofi comm on salt. The precipitate organic base the chemical composition of whichlcorresponds to that of a methyl deriva- The said base forms The'hydrochlorate presents the appearance of Well-defined crystals, varying in size from small prismatic needles to large prisms, some- ;5 times-possessing a length of several centime 1 ters and an according thickness. exhibit a metallic green or bronze-1ike luster.

The crystals They contain water of crystallization, which they lose upon beingdried in the water-bath.

4o-They dissolve in water with a bright bluishpurple color Their concentrated aqueous solution. upon being mixed with a concen I trated a JIGOHS solution of. oxalic'acid, sepa-. rates the oxalate in the form of glistening metallic green crystals.

From the ordinary methyl violets or pur .ples, wh ch are mixtures of various coloringv matters,; and are hitherto known in commerce only under the appearance of amorphous powders or lumps, my newcrystallized methyl:

violet principally differs by its crystallized..=

condition and by its uniformity of compost tion, in consequence of which propertiesitis capable of producingmore'unitbrm and superior results in its application as a; dye-stufl" or coloring-matter than those up to the present known. Crystallized methyl-violet dyes upon textile fiber a bluish-purple shade similar in tint, but brighterthan the shade produced by the benzylated derivative of ordinarymethyL violet known in commerce as methyl-violet \Vhat Ijcln m as; w, and desire to secure byLettersl cut, is- I j An improved! process ,of manufacturing crystallized methyl-violet by treating tetra methyl diamido benzophenone with reducing or hydrogenizing' agents, combining tetramethyl-diamido-'benzhydrole, the hydrogenized product thus obtained, withdim'ethyh aniline, submitting the result of such combination to an oxidizing process and crystallizing the dye-stuff or coloringmatter thus produced from its solution in suitable'sOh-ehts,substantially in the manner herein before described.

In testimony whereof I have hereunto set my. hand and seal in the presence of two 'sub-. scribing witnesses. ALFRED KERX. [L s] Witnesses:

X. Hnxzr, F. FOFACKER. 

